diff options
| author | Andrzej Hajda <a.hajda@samsung.com> | 2017-02-23 17:47:26 +0100 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2017-04-21 14:00:16 +0200 |
| commit | b917d4fd5050e46979835486a70c99b5cb688689 (patch) | |
| tree | a93cdfc8935cfb6bc35050d790bb2f8f2e8be436 /drivers/i2c | |
| parent | c7f82ea8605627b3088f166d9f4a5ca7857e8383 (diff) | |
| download | linux-b917d4fd5050e46979835486a70c99b5cb688689.tar.bz2 | |
i2c: exynos5: simplify timings calculation
Instead of using cryptic loop direct calculation of timings
can be used.
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Andi Shyti <andi.shyti@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-exynos5.c | 40 |
1 files changed, 14 insertions, 26 deletions
diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c index 736a82472101..5f24c3ef7d1d 100644 --- a/drivers/i2c/busses/i2c-exynos5.c +++ b/drivers/i2c/busses/i2c-exynos5.c @@ -292,9 +292,9 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, int mode) unsigned int t_sr_release; unsigned int t_ftl_cycle; unsigned int clkin = clk_get_rate(i2c->clk); - unsigned int div, utemp0 = 0, utemp1 = 0, clk_cycle; unsigned int op_clk = (mode == HSI2C_HIGH_SPD) ? i2c->hs_clock : i2c->fs_clock; + int div, clk_cycle, temp; /* * In case of HSI2C controller in Exynos5 series @@ -305,33 +305,21 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, int mode) * FPCLK / FI2C = * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + FLT_CYCLE * - * utemp0 = (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) - * utemp1 = (TSCLK_L + TSCLK_H + 2) + * clk_cycle := TSCLK_L + TSCLK_H + * temp := (CLK_DIV + 1) * (clk_cycle + 2) + * + * Constraints: 4 <= temp, 0 <= CLK_DIV < 256, 2 <= clk_cycle <= 510 + * */ t_ftl_cycle = (readl(i2c->regs + HSI2C_CONF) >> 16) & 0x7; - utemp0 = (clkin / op_clk) - 8; - - if (i2c->variant->hw == HSI2C_EXYNOS7) - utemp0 -= t_ftl_cycle; - else - utemp0 -= 2 * t_ftl_cycle; - - /* CLK_DIV max is 256 */ - for (div = 0; div < 256; div++) { - utemp1 = utemp0 / (div + 1); - - /* - * SCL_L and SCL_H each has max value of 255 - * Hence, For the clk_cycle to the have right value - * utemp1 has to be less then 512 and more than 4. - */ - if ((utemp1 < 512) && (utemp1 > 4)) { - clk_cycle = utemp1 - 2; - break; - } else if (div == 255) { - dev_warn(i2c->dev, "Failed to calculate divisor"); - return -EINVAL; - } + temp = clkin / op_clk - 8 - t_ftl_cycle; + if (i2c->variant->hw != HSI2C_EXYNOS7) + temp -= t_ftl_cycle; + div = temp / 512; + clk_cycle = temp / (div + 1) - 2; + if (temp < 4 || div >= 256 || clk_cycle < 2) { + dev_warn(i2c->dev, "Failed to calculate divisor"); + return -EINVAL; } t_scl_l = clk_cycle / 2; |